This is my favorite Commander deck (uploaded from my other account). I'd call it mid power probably a 5-6 on the CommandZone scale. Attack to trigger Dethrone then recur your creatures for value. 
One nice thing about this deck is it can still function without Marchesa in play. Mikaeus can give creatures undying, Impersonator and Metamorph can copy your opponents' best creatures, Fallen Shinobi can sneak in to get free cards, Scourge of the Throne can get extra attack phases. Resolving Sneak Attack with a way to protect it (Fierce Guardianship, Cryptic Command) can be a complete blow out--Marchesa will bring all the Sneak Attack creatures back onto the battlefield on your end step. 

Consider these lines of play: 

1. Damage: my favorite damage loop is Marchesa + Flayer of the Hatebound + Sac outlet. Sac Flayer => comes back with Undying dealing 5 damage to a target => Sac Flayer again => comes back at end of turn from Marchesa's ability dealing 4 damage to target. Note that because of Marchesa's ability you can do this loop once each turn (yours and opponents) for a total of 36 damage per rotation. Add Purphoros to this combo and you get and additional 4 damage to each opponent per turn. I personally avoid Purphoros--he's way too high threat and people simply kill you. If you need to end the game, slam down Warstorm Surge to double the damage for 18 per turn. 

2. Draw: Marchesa or Mikaeus + Mulldrifter/Baleful Strix + Sac outlet. Attack with creature to get a counter (if using Marchesa) => Sac creature and draw on ETB. For extra draw, use Grim Haruspex to draw for the ETB + Haruspex ability. 

3. Kill stuff: Marchesa or Mikaeus + Creature + Sac outlet. If the sac outlet is Attrition for 1 black mana you destroy a non-black creature. With Grave Pact each opponent sacs a creature. This should wipe the board fairly quickly. 

4. Tutor: this is low key the best synergy in the deck. Use Marchesa/Mikaeus + Sidisi + sac outlet. Do the loops outlined above. For every Sidisi ETB you tutor for a card. The value is absolutely absurd, allowing you to tutor for a timely counterspell, Deadly Rollick, board wipe, sac outlet, or finisher.